Explosive mechanism



May 2, 1939. R, M NARDONE 2,156,666

EXPLOSIVE MECHANISM I Original Filed May 29, 1930 3 Sheets-Sheet. l

Je?" e 124 y IN V EN TOR.

May 2, 1939. R. M. NARDONE 2,156,656

EXPLOSIVE MEGHANISM Original Filed May 29, 1930 3 Sheets-Sheet 2 IN VEN TOR.

Romeo M. /Va/aone May 2, 1939- R. M. NARDONE A 2,156,666

EXPLOS IVE MECHAN ISM Original Filed May 29, 1930 3 Sheets-Sheet 3 74.9 129 64 146 I4 9 Zd 55 26' 157 127 132 WPI/@.4

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IN VEN TOR.

Home@ M. /Va/aone Patented May 2, 1939 UNITED STATESv PATENT 'ortica EXPLO SIVE MECHANISM Original application May 29, 1930, Serial No.

457,301. Divided and 1935, Serial No. 24,910

2 Claims.

This invention relates to cartridge firing mechanism and more particularly to a device of this character adapted for use as an engine starting instrumentality. This application is a division of my co-pending application, Serial Number 457,301, filed May 29, 1930, Patent No. 2,025,884.

An object of the invention is to provide a cartridge firing device in which the ignition of the explosive charge is brought about automatically in response to a predetermined degree of rotation of a control element (the control element, in the illustrated embodiment of the invention, being the cranking shaft of an engine starting mechanism) This and other objects will appear more fully in the detailed description of the invention which follows. Although two embodiments of the present invention are described and illustrated in the accompanying drawings, it is to bte expressly understood that these drawings are for the purposes of illustration only and are not to be construed as a limitation of the scope of the invention, reference being had for this purpose to the appended claims.

In the drawings:

Fig. 1 is a side elevation partly in section of one embodiment of the present invention;

Fig. 2 is a front elevation of the embodiment shown in Fig. 1 with a portion of the pistol mech- 30 anism in section;

Fig. 3 is a front elevation similar to Fig. 2 showing a second embodiment of the pistol mechanism;

Fig. 4 is a bottom end 35 magazine shown in Fig. 3;

Fig. 5 is aside view of means shown in Fig. 3.

view of the cartridge and the magazine rotating.

Referring now to the drawings, wherein like reference characters indicate like parts through- 40 out the several views, the embodiment of the present invention disclosed in Figs. 1 and 2 comprises an automatic pistol mechanism which is adapted to fire a succession of explosive cartridges and thereby generate a fluid*` under pressure for 45 supply to a uid pressure engine having a crank shaft connectedto the rotatable elements of ai starting' mechanism for an internal combustion engine. These elements are suitably housed and supported in a main casing member 50 detachably connected as by bolts I to a portion of the casing S of the engine to be started. Casing member 6 when viewed from the outer-,endy as indicated in Fig. 2 is substantially circular in cross-section, but is provided with an internally 55 threaded boss 9 extending outwardly from its sub- 6 which is this application June 4,

stantlally cylindrical surface, into which is threaded a cylinder Ill for the fluid pressure engine. open and an end plate II is secured thereto by any suitable means as shown, and this plate provides both 'a closure for said open end and a bearing for the fluid pressure crank shaft and the manual actuating means later to be described.

By thus providing the major portion of the starter casing in three parts, simplicity and ease of manufacture and assembly are insured, together with ruggedness of construction. Further, to facilitate assembly, inspection, and maintenance, a hand-hole bottom of casing 6, a base plate I3 normally closing saidopening and being detachably secured to casing 6 by any suitable means as by screws I4 The uid pressure engfhe which supplies the starting torque to the engine to be started through the driving means later to be described, may be of any suitable construction, but as shown herein, comprises a single cylinder, reciprocating uid pressure engine having a piston I5 housed within cylinder I 0 and suitably secured as by a wrist pin I6 and a connectingv rod Il to a crank pin I3 which is formed as an integral part of a crank shaft I9, the outer end of which is suitably journaled in a bearing sleeve 20 and boss 2| formed in end plate Il. Both crank pin I8 and crank shaft I9 are made hollow for the purpose of reducing weight, and economy of space is also obtained by providing crank shaftv I 9 with a pair of circular anges 22 and 23 integral with the ends of crank pin I8 for purposes later to be described.

Suitable driving means are provided for transble member of the engine to be started for starting purposes. In the form shown, a driving member 24, which is preferably in the form of al clutchv jaw having inclined teeth and adapted to engage a similarly formed clutch jaw 25 carried- The outer end of casing member 6 is I2 may be provided in the mitting the torque of crank shaft I9 to a rotata- 2 nut 21 which is drivably connected to said barrel member by means of a friction clutch comprising a plurality of friction discs 28 which are splined alternately to the interior of barrel member 26 and the exterior of nut 21. Discs 28 are maintained in proper operative position between member 26 and nut 21 by means of an annular spacing member 29 interposed between the outermost friction disc and the inner face of flange 23, and by a second spacing member 30 placed between the innermost friction disc and a shoulder 3l formed integrally with nut 21. The alternate friction discs 28 are resiliently urged into frictional engagement with one another by means of a plurality of coil springs 32 which bear against a thrust plate 33 adjacent shoulder 3| and which exert their thrust against an annular, exteriorlythreaded nut 34 which is threaded into the interior of barrel member 26 and adapted to be locked in any desired position by suitable means such as a small locking plate 35 secured to nut 34 as by a screw 36 and projecting into one of a series of longitudinal slots 31 formed in the periphery of the outer end of barrel member 26. If desired, a ring 38 provided with studs 39 may be employed to maintain coil springs 32 in spaced relation within the barrel member 26, and it will be understood that the pressure of said springs may be suitably adjusted by means of nut 34.

Any rotation of nut 21 received from driving barrel member 26 through the medium of the friction clutch will be transmitted to driving member 24 by means of an exteriorly threaded screw shaft 40 which isV threaded within nut 21 and splined at its inner end to a hub 4| of driving member 24. A stop nut 42 is provided on the outer end of screw shaft 40 in order to limit the inward motion of said shaft by abutting against a shoulder 43 formed interiorly of nut 21. Screw shaft 40 is provided with a hollow bore through which extends a rod 44 which is adapted to limit the movement of driving member 24 relative to screw shaft 40. For this purpose rod 44 is provided with an enlarged head 45 at its outer end which abuts the outer end of screw shaft 40, and at its inner end with a slotted nut 46 limiting the inward movement of driving member 24. A coil spring 41 is provided adjacent the inner end of rod 44 for resiliently urging driving member 24 inwardly toward engine clutch jaw 25, said spring 41 being seated in a recess 48 formed in the inner end of screw shaft 4I), surrounding rod 44 and exerting its thrust against the inner face of driving member 24.

Driving member 24 is normally disengaged from engine nember 25 and suitable means are 'therefore provided for advancing said driving member into cranking engagement with the engine member. As shown, said means are pref- ,erably constituted so as to be automatic in operation upon initial rotation of crank shaft I9 yand the driving means, and comprise a plurality y of longitudinally*'disposed slots 49 formed in the louter periphery of driving member 24 which are adapted to receive radial lugs 50 which project l inwardly from the inner surface of a split ring 5| which is supported on the curved lip 52 of anoil-sealing member 53 `which surrounds the inner end of the driving mechanism and is suitably secured between casing member 6 and engine casing 8. The three parts of split ring 5| are preferably retained in position on oil-sealing member 53 by means of a surrounding resilient member such as a coil spring 54. An oil-tight seal is formed around hub 4| of driving member 24 by means of a packing ring 55 of leather or other appropriate material which is suitably secured to member 53 as by means of a plate 56 and rivets 51.

Referring now to the source of supply of the fluid under pressure which is used as the motive force for the fluid pressure engine, an automatic pistol mechanism has been provided which is adapted to fire a succession of explosive cartridges and thereby generate a fluid under high pressure, the timing of said explosions being synchronized with the operation of the uid pressure engine by suitable means driven from the engine crank shaft, and the high pressure iiuid thus produced being supplied to the cylinder of the uid pressure engine by suitable means so as to act upon the piston of said engine. In the form shown in Figs. 1 and 2, a pistol barrel 58 is mounted in a vertical position adjacent cylinder |0 and supported by and secured to main casing 6 by any suitable means such as a pair of flanges 59 and 60 and a screw 6|. A pipe or conduit 62 connects the upper end of pistol barrel 58 with cylinder IIJ of the fluid pressure engine, and constitutes a cartridge explosion chamber for the pistol mechanism and a passageway for conducting the fluid produced by the explosion to the fluid pressure engine. The connection between pipe 62 and pistol barrel 58 may be made in any suitable manner as by means of a threaded nipple 63 formed on the end of pipe 62 and screwing into the interior of barrel 58, the connection being made gas-tight by means of a suitable gasket 64 interposed between the abutting surfaces of the two members. Suitable means are also provided for connecting the other end of pipe 62 to the cylinder |0 of the uid pressure engine, which as shown, comprise an exteriorly threaded fiange 65 formed on the end of pipe 62 which abuts a similar ange 66 formed as a part of a gland 61 which is threaded into the interior of a boss 68 formed integral with the top of cylinder l0, to form an antechamber directly above said cylinder, and a cupshaped nut 69, the threads of which engage the threaded ange of pipe 62 while the inside of its head bears against flange 66 of gland 61. A suitable gasket is also provided between the abutting surfaces of flanges 65 and 66 in order to make the joint gas-tight.

A cylindrical cartridge magazine 1| is positioned alongside of pistol barrel 58 and is secured thereto by any suitable means as a bracket 12 on which the bottom of the magazine rests and a strap 13 encircling magazine 1| and pipe 62. The top of magazine 1| is provided with a removable cap 14 to facilitate the loading of the magazine with a plurality of explosive cartridges, and the lower portion of said magazine communicates directly with the interior of pistol barrel 58 through cooperating openings in the sides of said members so as to allow the transfer of cartridges from magazine 1| to the interior of pistol barrel 58, by suitable loading mechanism later to be described. It is to be understood that magazine 1| may be of any desired size so as to accommodate a sufficient number of cartridges for one or more starting operations.

Mounted within pistol barrel 58 so as to be longitudinally slidable therein, is provided suitable mechanism for performing the loading, firing, and ejecting operations of the pistol apparatus, which, in the form shown, comprises a bolt mechanism adapted for reciprocating movement within pistol barrel 58, a firing pin housed within and capable of limited movement relative to said bolt mechanism, a cartridge positioning lever, and an extractor. The bolt mechanism comprises a piston-like breech plug 15 which is slidably mounted in and of substantially the same diameter as the bore of barrel 58, and a carrier 16 which is threaded to the exterior lower portion of breech plug 15 and which is slidably mounted within the lower enlarged portion of barrel 58. Carrier 16 is provided with a cam follower or roller 11 suitably supported on a stub shaft 18 and adapted for engagement with a driving cam 19 which is secured to an extension 80 of crank shaft |9 by any desirable means such as a key 8| and lock nut 82. Carrier 16 is resiliently urged downwardly by a coil spring 83 interposed between a shoulder formed in barrel 58 and a similar shoulder formed in carrier 16 so as to maintain cam follower 11 in contact with cam 19 at all times. A reciprocating motion is thereby imparted to carrier 16 andthe remainder of the bolt mechanism, which, by appropriate designing and setting of cam 19, will be synchronized with the operation of the uid pressure engine.

A firing pin 84 having a striking point 85 is housed within breech plug 15 and normally occupies the position shown in Fig. 1 wherein a spring 86 surrounding firing pin 84 Within a recess 81 formed in breech plug 15 exerts its thrust against a collar 88 formed on firing pin 84 and forces said firing pin to the upper limit of its travel relative to breech plug 15. In this position collar 88 bears against the upper end of recess 81 and striking point 85 of the firing pin projects slightly above the surface of a recessed seat 89 formed in the upper face of breech plug 15 and adapted to receive the base of an explosive cartridge. A gland 90 is threaded into the interior lower portion of breech plug 15 and acts both as a seat for spring 86 and a guide for a sleeve 9| which is threaded onto-the lower portion of firing pin 84.

The position of firing pin 84 described in the preceding paragraph and shown in Fig. l is the position said pin would occupy after a cartridge had been fired. In order to iire a cartridge, however, it is necessary to cock the firing pin by withdrawing the striking point 85 below the Surface of seat 89 and to retain it in said withdrawn position until the cartridge to be fired has been fully seated within the explosion chamber and the bolt mechanism has reached the limit of its upward travel. To perform this cooking and firing operation, suitable means are provided which comprise a trigger engaging finger or lug 92 which is formed integral with and projects laterally beyond the surface of sleeve 9| and extends through a longitudinal slot 93 formed in carrier 16. The outer end of lug 92 also extends within a longitudinal slot 94 formed in the lower portion of pistol barrel 58. This construction allows longitudinal movement of lug 92, sleeve 9| and firing pin 84 withlthe bolt mechanism relative to barrel member 58, and also allows a limited longitudinal movement of said parts relative to the bolt mechanism itself. Adjacent the upper limit of the longitudinal movement of carrier 15 there is provided a trigger member 95 pivotally supported on pistol barrel 58 as on a pin 96 which may be mounted in a bracket indicated at 91.. Trigger 95 is provided at its upper end with a recess 98 within which there is seated a. small coil spring 99 which bears against the surface of barrel 58 and urges this end of trigger 95 resiliently outwardly from said barrel. The. lower. end of trigger 95 is provided with an inclined cam surface and a tooth-shaped detent |0| which occurs, firing pin 84 is held against further 11pward movement. Carrier 16 and breech plug 15, however, continue their upward movement and in sodoing compress spring 86. This upward movement reaches its limit (indicated at point B on cam 19) when atrigger operating member |02 which is threaded intov carrier 16 below and in line with slot 93, engages cam surface |00 of trigger 95 and rocks the latter around pin 96 against the tension of spring 99. Detent |0| is thereby withdrawn from lug 92 and the latter is released to allow firing pin 84 to be moved rapidly upward relative to breech plug 15 by the action of spring 86, causing striking point 85 to impinge against the bottom of a cartridge which has previously been positioned within seat 89 by mechanism later to be described, and causing an explosion.

Referring now to the cartridge positioning means, as shown in Fig. 2, a cartridge positioning lever |03 is pivotally supported in any suitable manner, as on a pin |04 supported in a bracket indicated at formed integral with barrel 58, and its upper arm extends within the lower portion of cartridge magazine 1| through a slot |06 formed in the bottom and side of said magazine. The lower arm of lever |03 bears against a cam surface |01 formed integral with carrier 16 and projecting through a longitudial slot |08 formed in the lower portion of barrel 58. In the position shown in Fig. 2, the bolt mechanism is at the lower limit of its longitudinal movement and is ready to begin the loading operation. The lower arm of cartridge positioning lever |03 is 0n the lowest point of cam surface |01 and the upper arm of said lever is in its extreme outer position which allows an unexploded cartridge |09 to drop to the bottom of magazine 1| ready to be moved to the right as viewed in Fig. 2 by the upper arm of cartridge positioning lever |03. As the bolt mechanism moves upwardly under the action of cam 19, the lower arm of lever |03 rides up on the face of cam surface |01 and the upper arm of said lever pushes the unexploded cartridge |09 to the right and positions the same on top of breech plug 15, so that continuing upward movement of the bolt mechanism will carry said cartridge within the bore of pipe 62 and seat it in its proper position for firing. At this time firing pin 84 will be Withdrawn within the bolt mechanism so that striking point 85 is below the surface of seat 89, and the extractor rim ||0 of cartridge |09 will be fully seated within said seat.

As the limit of upward movement of the bolt mechanism is reached, the firing pin is released as previously described and under the force of spring 86, striking point 85 is driven against the base of cartridge 09 causing an explosion, the fluid thus produced being conducted to the fluid pressure engine through the interior of pipe 62. The expansion of the fluid forces piston |5 of the fluid pressure engine downward thus rotating crank shaft 9 and the driving means. After about 120 degrees of the downward stroke of piston I5, an exhaust port in the side of cylinder I is uncovered and allows the expanded fluid to escape to the atmosphere. Cam 19 is so constructed, as shown in Fig. 2, that the bolt mechanism will be maintained at the limit of its upper travel from thetime cartridge |09 is fired (indicated at C) until exhaust port |I| is opened (indicated at D), thus preventing any escape of the fluid under pressure through the pistol mechanism and thereby insuring that the maximum amount of energy obtainable from said iiuid will be exerted upon piston I5.

As the bolt mechanism begins its downward movement, a spring extractor I I2 which is secured within a longitudinal recess formed in the periphery of the upper end of breech plug and which has a toothed head ||3 normally resiliently urged to the left as viewed in Fig. 2, but having been forced to the right by inclined surface 63a to allow cartridge |09 to be fully seated in recess 89 and in the explosion chamber, will clamp extracting rim ||0 of the cartridge |09 and cause said cartridge to be withdrawn from the bore of pipe 62 and carried downwardly with the bolt mechanism. As the bolt mechanism approaches the lower limit of its longitudinal movement, the upper arm of lever |03 will begin to move to the left as viewed in Fig. 2 and to allow an unred cartridge, which has previously been prevented from falling to the bottom of magazine 1| by means of the bent-over end ||4 of said le- Ver, to drop towards the bottom of said magazine ready for another load. When the bolt mechanism again begins its upward movement, the cycle previously described will be repeated and the unexploded cartridge in being moved to the right by lever |03 and positioned on top of breech plug 15 will eject the empty cartridge through a port I |5 formed in the side of barrel 58.

Although the successive explosions produced by the pistol mechanism thus' described are automatically regulated by means of cam 19 which is driven from crank shaft I9 of the fluid pressure engine, means must be provided for causing the initial explosion and for commencing the operations of the fluid pressure engine. Said means are preferably adapted for manual operation by the operator of the internal combustion engine which is to be started, and in the form shown comprise manual cranking means which are drivably connected to crank shaft I9 of the uid pressure engine. A cranking shaft ||6 is rotatably supported in a bearing sleeve ||1 in a boss I I8 formed in end plate II at right angles tothe axis of crank shaft I9. The inner end of shaft ||6 is provided with`a bevel gear ||9 secured thereto b-y any suitable means including a nut and washer |2| which meshes with a large bevel gear |22 secured to flange 22 of crank shaft I9 in any suitable manner (not shown). The outer end of cranking shaft II6 is provided with a cylindrical crank head |23 which is secured thereto as by means of a shear pin |24 and provided with a cranking pin |25 having outwardly projecting ends |26 adapted to be engaged by an ordinary hand crank. Rotation of cranking shaft H6, which is in turn transmitted to crank shaft I9 of the iiuid pressure engine, will not only actuate the pistol mechanism so as to cause an explosion and thereby operate the fluid pressure engine by the force thereof, but will also, through barrel 26 Which is secured to crank shaft I9, impart rotation to the driving means and cause engagement of driving member 24 with engine member 25 by means of the automatic engaging mechanism previously described. By this means it is possible to move driving' member 24 into engagement with engine member 25 prior to the explosion produced by the pistol mechanism, and thus obtain the benefit of the full amount of energy created by the explosion for cranking purposes, none of it being expended in the preliminary step of causing cranking engagement of the members. It will also be understood that should the supply of explosive cartridges become exhausted, the starting operation may still be performed manually by the rotation of cranking shaft ||6.

As previously described, and as shown in Fig. 2, end plate I I is detachably secured to main casing member 6 by a plurality of screws. These screws are preferably provided at equally spaced intervals around the periphery of plate so that said plate may be secured with cranking shaft ||6 in any desired position as indicated by the dotted lines of Fig. 2, so as to facilitate cranking.

A second embodiment of the pistol mechanism is illustrated in Figs. 3, 4, and 5, and differs from the embodiment shown in Figs. 1 and 2 only in the construction of the cartridge magazine and loading means. As shown, a rotary magazine |26 provided with a plurality of cartridge recesses |21 is rotatably supported in a vertical position on, a pin |28 between a pair of flanges |29 and |30, Which may be formed integral with barrel 58, and extends within the barrel in such a manner that, as the magazine rotates, each of the,

cartridge recesses |21 may in succession be centered with respect to the bore of barrel 58 and the bolt mechanism. Each recess |21 is provided at its lower end with a plurality of projections |3I, preferably three in number, which are integral with magazine |26 and extend radially inwardly from the periphery of the recess to form a seat for the bottom of an explosive cartridge |32.

After a cartridge has been positioned concentrically with the bore of barrel 58 by the magazine rotating means later to be described, the bolt mechanism is adapted to move upwardly through recess |21 and to advance cartridge |32 to its proper firing position within the explosion chamber of pipe 62. For this purpose breech plug 15 is provided in its periphery with a plurality of longitudinal grooves |33 which correspond to and are adapted to receive projections |3| during the upward travel of the bolt mechanism. When cartridge |32 is fully seated, it is fired in a manner similar to that previously described in connection with Figs. 1 and 2.

The extracting means for withdrawing the empty cartridge case |32 from pipe 62 after the explosion comprises a. spring extractor |34, similar to extractor ||2, secured by any suitable means to the outer surface of breech plug 15 in the same vertical plane with pin |28 and provided with a toothed head |35. The normal tension of spring extractor 34 maintains head |35 in the position shown in Fig. 3, away from the top of breech plug 15, as long as it moves within a longitudinal groove |35 formed in the inner wall of barrel 58, the upper end of which extends above the lower portion of magazine |26. This construction allows the bolt mechanism to move upwardly and engage the bottom of cartridge |32 before the extractor is resiliently urged inwardly by the cam-like construction of the upper end of groove |36 so as to cause toothed head |35 to project within a longitudinal peripheral groove |31 formed in the magazine |26 and communicating with recess |21, and to engage the extracting rim of the cartridge. After the cartridge has been fired, this toothed engagement of head |35 with rim ||0 will withdraw or extract the empty cartridge case from the explosion chamber and return it to recess |21 within magazine |26, the toothed engagement being released by the spring action of extractor |34 when groove |36 is reached in the downward travel of the bolt mechanism.

Suitable means must also be provided for automatically rotating magazine |26 after each cartridgg is red in order to present a fresh one for the next load, which, as shown, may comprise a magazine operating leverl |38 secured at its lower end to a hub |39 which is pivotally mounted on a pin |40 supported in a pair of brackets indicated at |4| as projecting from the surface of barrel 58, and having at its upper end a pivotally mounted finger |42 which is adapted to engage one of a plurality of lugs |43 circularly arranged on the bottom of magazine |26. Hub |39 is also provided with a short arm or cam follower |39, similar to the lower arm of lever |03 shown in Fig. 2, which bears against cam |01 of carrier 'I6 and acts in a manner similar to that previously described in connection with lever |03 to rock lever |38 about its pivot and, due to the engagement of finger |42 with lugs |43, to rotate maga- Zine |26 so as to successively bring the various recesses |21 in line with the bore of the pistol mechanism. Finger |42 is pivoted as on a pin |46 and is provided with a suitable spring |45 so as to maintain its normal position as shown in Fig. 3 when rotating the magazine, and yet to allow it to resiliently yield when passing over the next lug on the return movement of lever |38.

Each recess |21 is accurately centered with the bore of the pistol mechanism, and magazine |26 is held against further rotation after being thus centered, by means of a detent MB which is housed in and projects from the bottom of upper flange |29, and is resiliently urged into engagement with one of a plurality of depressions |41 `suitably formed and located in the upper end of magazine |26, by means of a small spring |68 which is compressed Within the recess housing detent |46 by a suitable screw |419.

With this type of magazine, in order to load a fresh supply of explosive cartridges, it is only necessary to withdraw pin |28 and remove magazine |26, either replacing it with a full one or reloading and replacing the one removed by dropping a cartridge into each recess |21 from they top, projections |3| forming a seat thereforand preventing the cartridge from dropping through the magazine.

Describing now the operation of the present invention, the operator of the internal combustion engine to be started first loads the cartridge magazine with a plurality of unexploded cartridges so as to provide sumcient ammunition to produce a sufficient number of successive explosions to insure a successful start. An ordinary hand crank is then fitted to the end of cranking shaft HB and is rotated slowly until driving member 2B has been fully engaged with engine member 25 due to the rotation of driving barrel 26 and the cooperation of the rest of the driving mechanism as previously described. At the same time, this initial rotation of cranking shaft ||6 has caused rotation of cam 19 and through roller 11 has moved the bolt mechanism of the pistol means upward from its lowermost position (indicated at A in Fig. 2), thus starting to move a cartridge upward toward its firing position within the lower portion or explosion chamber of pipe 62. As cranking shaft |6 continues to be rotated,` the bolt mechanism will be further advanced upwardly towards ring position, and, at point B on cam 19, lug 92 engages detent |0| of the trigger mechanism and the cocking operation is started. Still further rotation advances the bolt mechanism until point C on the cam is reached when trigger operating member |02 forces detent |0| outwardlyso as to release lug 92 and allow the firing pin to be rapidly forced upwardly against the base of the cartridge which is now securely seated within the explosionchamber. As previously described, cam 19 is so formed that when the explosion takes place, piston I5 is at the top of its stroke. The fluid which is produced as a result of the explosion of the cartridge is under very high pressure and is conveyed through pipe 62 to the interior of cylinder l0 and there acts upon piston 5 so as to force it rapidly downward, said movement being transmitted to crank shaft |9 and through driving barrel 26 and the remainder oi the driving means to the engine member 25, thus cranking the engine to be started.

The hand crank attached to cranking shaft |6 will be automatically disengaged upon the first explosion due to the usual pin and slot connection, and subsequent explosions will be produced automatically by the rotation of crank shaft i9 under the action of the fluid pressure engine. The engine to be started will thus be continuously cranked until it starts under its own power at which time members 26 and 25 are disengaged due to the action of the inclined teeth, driving memrelative motion between nut 21 and driving barrel 26 and thus protect the starter parts from injury. Should, for any reasons, a supply of unexploded cartridges be unavailable, the starting operation lmay be performed manually as previously dev scribed by rotating the hand crank attached to cranking shaft i6.

What is claimed is:

1. A cartridge firing device comprising a rotatable shaft, a cam mounted thereon, a follower associated with said cam, means for resiliently urging said follower into contact with said cam, a bolt mechanism operatively connected with said follower. a firing pin mounted within said bolt mechanism and normally movable therewith, and means for restraining the movement of said cam follower to a predetermined rectilinear path.

2. A cartridge ring device comprising a rotatable shaft, a cam mounted thereon, a cam follower and firing pin movable along coaxial paths in response to the rotation of said shaft and cam, means for restraining the movement of said firing pin, land means for automatically releasing said 

